Method and kit for treating recreational water

ABSTRACT

Provided herein is a method for reducing down-time in a recreational body of water having a water filtering system and water recirculation system after a potential release of  Cryptospridium  oocyst and/or  Giardia  cysts. Also described is a kit for practicing the method for reducing down-time in a recreational body of water that may have a potential release of  Cryptospridium  oocyst and/or  Giardia  cysts.

RELATED APPLICATION

The present application is based upon and claims priority to U.S.Provisional Application Ser. No. 61/816,369 filed on Apr. 26, 2013,which is incorporated herein by reference.

FIELD OF INVENTION

The present invention relates to a method and kit used to treatrecreational water after a fecal release in the recreational water, inparticular a fecal release which may include a release ofCryptosporidium and/or Giardia.

BACKGROUND OF THE INVENTION

The Cryptosporidium is a waterborne parasitic protozoan responsible forthe waterborne disease Cryptosporidiosis. Outbreaks of Cryptosporidiosishave been attributed to ingestion of drinking water, recreational wateror food containing viable oocysts of Cryptosporidium. Cryptosporidiumoocysts are typically introduced into the water through contamination ofthe water with fecal matter from cattle or humans containing oocysts.The oocysts have a hard outer cell wall that renders the oocystsresistant to the effects of chlorine present at concentrations typicalof drinking water and recreational water. The oocysts are approximately4-6 microns in size, which makes them difficult to remove by filtration.Since filtration and chlorination are universally practiced as a meansfor clarifying and sanitizing drinking water in municipal watertreatment facilities and for maintaining the clarity of recreationalwater such as in swimming pools, water parks, hot tubs, baths and spas,the chlorine resistance and size of the oocysts make it difficult toensure that water is free of this disease-causing microorganism.

A variety of filters and filter systems are used to clarify water inswimming pools, water parks, hot tubs and spas. Sand filters are commonfor swimming pool use and municipal water treatment. Diatomaceous earthfilters are also available for use in swimming pools and water parks.Cartridge filters available to both pools and spas utilize a syntheticfabric enclosed in a plastic cartridge. Different filter media exhibitdifferent capabilities for removing particles that vary in size. Sandfilters are capable of filtering out particles in the size range of25-50 microns, while cartridge filters are typically capable of removingparticles in the size range of 15-25 microns. Diatomaceous earth filtersexhibit the capability of removing particles in the size range of 5-10microns, but have to be replaced frequently.

Coagulation and flocculation followed by filtration is commonly utilizedin the treatment of drinking and recreational water to remove suspendedmicroscopic particles. Some suspended microscopic particles tend topossess an electrostatic charge that prevents the particles fromaggregating into larger filterable aggregates due to charge-chargerepulsion. For example, bacteria and Cryptosporidium oocysts have anegative surface charge. This can be often overcome through the use ofcoagulants and flocculants. Coagulants are chemicals, that whendissolved in water, form ions of charge opposite to that of thesuspended particles.

Flocculants are typically water soluble or water dispersible highmolecular weight polyelectrolyte long chain polymers composed ofrepeating monomeric units that can be categorized into inorganic ororganic compounds. The inorganic polyelectrolytes are polymerized metalsalts and may include polyaluminum hydroxychloride, polyaluminumsilicate sulfate and polyaluminum sulfate. Organic polyelectrolyteflocculants are derived synthetically or obtained from natural sources.The organic polyelectrolytes can exist as charged or uncharged polymersdepending on their composition. Flocculants when added to watercontaining aggregates of microscopic particles or non-aggregatedparticles exhibit the ability to bind and gather the particles orparticle aggregates into even larger aggregates that can be easilyfiltered.

It has also been suggested to treat recreational water possiblycontaining Cryptosporidium and/or Giardia by hyper-chlorination of thewater. Hyper-chlorination is a process in which additional free chlorineis added to the recreation water such that the water contains freechlorine at a level generally above about 10-ppm; typically in the rangeof about 10-50 ppm. However, hyper-chlorination alone is effective inkilling these parasites, in particular in killing Cryptosporidium butrequires long contact times in presence of cyanuric acid. Cyanuric acidis used to stabilize the free chlorine against degradation by sunlight.

These treatments have not been successful in removing Cryptosporidiumoocysts and/or Giardia cysts from recreational water, but requires thepool to remain closed to swimmers sometimes for days. As such, there isa need in the art for an effective method to remove Cryptosporidiumand/or Giardia from the recreational water and to remove them in amanner which is cost effective, timely and easy to manage. The presentinvention provides an answer to that need.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a method for reducingdown-time in a recreational body of water having a water filteringsystem and water recirculation system after a potential release ofCryptospridium oocyst and/or Giardia cysts. The method includes adding ahalogenating agent to the body of water to raise the concentration ofthe active halogen to a level between about 10 ppm and about 100 ppm andadding at least one agglomeration aid to the body of water at a levelbetween 0.1 ppm and 3.0 ppm. After addition of both the halogenatingagent and the agglomeration aid to the body of water, the water is thenrecirculated with the recirculation system through said filtering systemfor a period of time. After the period of time, the concentration ofactive halogen in the water is reduced to a level of between 1 and 9 ppmafter the water has been recirculated through the filtering system forthe period of time. In an additional aspect, a filtration enhancementaid may be added to the filtration system prior to recirculating thewater through the filtering system.

In another aspect of the present invention, provided is a method forreducing down-time in a recreational body of water having a waterfiltering system and water recirculation system after a potentialrelease of Cryptospridium oocyst and/or Giardia cysts. The method ofthis aspect includes adding a halogenating agent to the body of water toraise the concentration of the active halogen to a level between about10 ppm and about 50 ppm. In addition, a filtration enhancement aid isadded to the filtering system. Once the active halogen level is raisedand the filtration enhancement aid is added to the filtering system, thewater is then recirculated within the recirculation system through saidfiltering system for a period of time. After the period of time, thefiltering system is backwashed to remove any captured Cryptospridiumoocyst and/or Giardia cysts trapped by the filtering system. Next, theconcentration of active halogen in the water is reduced to a level ofbetween 1 and 9 ppm after the water has been recirculated through thefiltering system for the period of time and the filtering system hasbeen backwashed.

In an additional aspect of the present invention, provided is a kit fortreating a potential release of Cryptospridium oocyst and/or Giardiacysts in a recreational body of water. The said kit contains ahalogenating agent, an agglomeration aid for addition into the body ofwater and/or a filtration enhancement aid for addition into a filter; acyanuric acid test kit; and a chlorine neutralizing agent.

These and other aspects will become apparent when reading the detaileddescription of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It has now been surprisingly found that the time period for removal ofCryptospridium oocyst (Cryptosporidium parvum) and/or Giardia cysts(Giardia duodenalis) or rendering the oocyst or cysts inactive can begreatly reduced by following the methods of the present invention inconjunction with the kit of the present invention.

In recreational water, free chlorine is generally present in an amountunder 10 ppm, more typically in a 3 ppm to 6 ppm range. This level offree chlorine is sufficient to actively control most microbes in thewater to safe levels for human contact with the water. However,Cryptosporidium oocysts and Giardia cysts are generally not inactivatedwith this level of free chlorine in recreational bodies of waters suchas swimming pools, hot tubs, spas, water parks, and the like.

The first step of the methods of the present invention is tohyper-halogenate the body of water by the addition of a halogenatingagent to the body of water. The term “halogenating agent” as used hereinrefers to compounds having a halogen atom bound to a stronglyelectronegative atom such as oxygen, nitrogen, or another halogen, andcapable of donating a positively charged halogen atom. Representativehalogenating agents include, for example, sodium hypochlorite, lithiumhypochlorite, calcium hypochlorite, chlorine, hypochlorous acid,bromine, hypobromous acid, N-chlorosuccinimide, sodium hypobromite,pyridinium bromide perbromide, N-bromosuccinimide,dichlorodimethylhydantoin, bromochlorodimethylhydantoindibromodimethylhydantoin, dichloroisocyanurate, or trichloroisocyanurateand combinations thereof. Other suitable halogenating agents will bereadily apparent to those skilled in the art.

Hyper-halogenation, as used herein means a free halogen level greaterthan 10 ppm, and generally greater than 20 ppm. The upper limit tohyper-halogenation is not critical but is generally limited to about 100ppm. Above about 100 ppm, the chlorine in the water may become corrosiveto metal used in or around the body of water, can cause damage toplastic parts of the recirculation system, and can cause damage to poollines or coatings applied to the pool walls. Typically,hyper-halogentation will be in the range of about 10 ppm to about 100ppm, more typically between 10 ppm and 60 ppm, with the range of about20 ppm to about 50 ppm being typically used. These levels of freechlorine in the water have been found to oxidize the surfaces of bothCryptosporidium oocysts and Giardia cysts over a period of time. Theperiod of time can be several hours to several days, depending of theamount of the free chlorine and cyanuric acid in the recreational bodyof water.

Cryptosporidium oocysts and Giardia cysts are known to have negativecharges on their surfaces. As such, at least one agglomeration aid,which are positively charged, is added to the recreational watercontaining or potentially containing Cryptosporidium oocysts and Giardiacysts. The agglomeration aid, with its positive charge, serves toattract the negatively charged Cryptosporidium oocysts and Giardiacysts, or serves to reduce the negative charge of the Cryptosporidiumoocysts and Giardia cysts, allowing the oocyst and/or cyst to cometogether and agglomerate, by binding to the agglomeration aid, or byhaving a reduced charge and allowing the Cryptosporidium oocysts andGiardia cyst to come together forming a stabilized floc or agglomerationof the Cryptosporidium oocysts and Giardia cyst. This allows theagglomerated particles to be filtered by the filtration system.Agglomeration aids include flocculants and coagulants.

Suitable flocculants include, for example polyaluminum chloride,cationic polymers selected from the group consisting of polyamines,polyacrylamides polydiallyldimethylammonium chloride. Suitablecoagulants include, for example, metal salts, such as ferric chloride;aluminum sulfate and mixtures thereof.

The agglomeration aid is generally added to the recreational water in anamount of between 0.1 ppm and 3.0 ppm. The agglomeration aid may beadded continuously or it may be added as a “slug” or one-time addition.Care should be taken not to exceed the upper limit, since too much ofthe agglomeration aid in the recreational water may have a negativeeffect on agglomeration of the Cryptosporidium oocysts and Giardia cyst.

Recreational water can be associated with a recirculation system; therecirculation system generally has a pump, piping and a filteringsystem. Generally, the pump draws water from the recreational body ofwater through skimmer or drains in the pool and brings the water to thepump with piping. The pump pulls the water through the pump and into afiltration system. The filtration system is a single filter or a seriesof filters which are designed to remove particles from the waters.Exemplary water filtration systems include, for example, sand filters,diatomaceous earth filters or a cartridge filters.

As an alternative to the addition of an agglomeration aid, or inaddition to the agglomeration aid, a filtration aid may be added to thefiltration system to assist the filtration system in removingCryptosporidium oocysts and Giardia cysts from the water beingcirculated through the filtration system. Suitable filtration aidsinclude, for example, diatomaceous earth, cellulose, chitin, aluminumsulfate, perlite and mixtures thereof. In the case of sand filters, thefiltration aid may be added directly to the sand filter. The filtrationaid serves to coat the filtration particles, thereby assisting thefilter in removing Cryptosporidium oocysts and Giardia cyst from thewater, by trapping the oocyst and/or cyst in the filter.

Once the water is hyper-halogenated and the agglomeration aid and/orfiltration aid is added accordingly, the recirculation system is allowedto recirculate the water through the filtration system to remove theCryptosporidium oocysts and Giardia cyst present in the water. Theperiod of time may vary depending size of the pool and the capacity ofthe recirculation system. In any event, the method of the presentinvention is effective in reducing the amount of time necessary toinactivate and/or remove oocyst and/or cyst from the recreation water,as compared to using just one of the methods alone. As such the methodof the present invention allows the recreational water to be used with ashorter down time, meaning that the pool will be ready and safe for usein a shorter period of time. This method can be advantageous forcommercial and community swimming pools that are well used by the publicto effectively treat and prevent a potential outbreak ofcryptosporidiosis, and the like, due to contact commercial, municipaland community recreational water facilities containing Cryptosporidiumoocysts and Giardia cysts. The time reduction can be in the magnitude of2-10 fold.

Once water has been recirculated through the filtration system for aperiod of time, it is necessary to remove the trapped Cryptosporidiumoocysts and Giardia cysts from the filtration system. This isaccomplished by “back washing” the filter by reversing the flow of waterthrough the filter. Water that is back washed through the filter isgenerally sent to a drain which leads to a water treatment plant forfurther processing. Back washing releases the capture Cryptosporidiumoocysts and Giardia cysts from the filter and from the recreationalwater system. In addition to back washing, the body of the recreationalwater should also be vacuumed to remove any particles on the floor orwalls of the recreational water body.

Once the filtration system is backwashed, the free chlorine level in therecreation water must be returned to levels prior to hyper-halogenation,so that the recreational water can once again be enjoyed by users.Suitable halogen neutralizers include, for example sodium thiosulfate,sodium metabisulfite, hydrogen peroxide, etc. The free chlorine contentof the recreational water should be returned to the range of about 1-10ppm, generally between 3-6 ppm.

The time necessary to achieve inactivation and removal ofCryptosporidium oocysts and Giardia cysts form the recreational watercan also be dependent on other factors, including water temperature, pHand the presence of cyanuric acid. Cyanuric acid is present in pools asa stabilizer for free chlorine. However, cyanuric acid has been found toreduce the effectiveness of hyper-halogenation on a recreational body ofwater against Cryptosporidium oocysts. As such, the method of thepresent invention may further include determining the cyanuric acidlevel in the body of water prior to adding the halogenating agent. Atthis point, the cyanuric acid may be neutralized, or in the alternativethe amount of halogenating agent added to hyper-halogenate the body ofwater is based on the amount of the cyanuric acid level in the body ofwater. Generally, as the amount of the cyanuric acid goes up, the higherof the amount of the halogenating agent is used. Typically, the amountof halogenating agent added to the body of water is proportional to thelevel of the cyanuric acid in the body of water. As an alternative, acyanuric acid neutralizer may be added to the recreational water priorto hyper-halogenation.

Also provided by the present invention is a kit for treating a potentialrelease of Cryptospridium oocyst and/or Giardia cysts in a recreationalbody of water. The kit contains a halogenating agent; an agglomerationaid for addition into the body of water and/or a filtration enhancementaid for addition into a filter; a cyanuric acid test kit; and a chlorineneutralizing agent. Any of the halogenating agents, agglomeration aids,filtration enhancement aids, and chlorine neutralizing agents describedabove may be used.

The kit may also have instructions, a chart for specifying the amount ofthe halogenating agent based on the amount of the cyanuric acid. The kitmay be sized for particular size of a pool in terms of volume or may beprovided in incremental amounts, such as 5,000, 10,000 gallon or greaterincrements.

While the invention has been described above with references to specificembodiments thereof, it is apparent that many changes, modifications andvariations can be made without departing from the invention conceptdisclosed herein. Accordingly, it is intended to embrace all suchchanges, modifications, and variations that fall within the spirit andbroad scope of the appended claims.

What is claimed is:
 1. A method for treating a recreational body ofwater having a water filtering system and a water recirculation systemafter a release of Cryptosporidium oocyst and/or Giardia cysts, whereinthe recreational body of water has an initial active free halogenconcentration between about 1 ppm and about 8 ppm, said methodcomprising: (i) adding a halogenating agent to the recreational body ofwater to raise the concentration of the initial active free halogen to alevel between about 10 ppm and about 100 ppm; (ii) adding anagglomeration aid to the recreational body of water at a level between0.1 ppm and 3.0 ppm, adding a filtration enhancement aid to saidfiltering system, or adding both an agglomeration aid to therecreational body of water at a level between 0.1 ppm and 3.0 ppm andadding a filtration enhancement aid to said filtering system; (iii)recirculating water from the recreational body of water with said waterrecirculation system through said water filtering system for a period oftime; and (iv) reducing the concentration of active free halogen to alevel of between 1 and 8 ppm in order to return the concentration ofactive free halogen to a level prior to adding the halogenating agent.2. The method according to claim 1, wherein the filtration enhancementaid is added to the water filtering system and the method furthercomprises back washing the water filtering system.
 3. The methodaccording to claim 1, wherein the agglomeration aid is added to therecreational body of water and the filtration enhancement aid is addedto the water filtering system, and further comprising a step ofbackwashing the water filtering system.
 4. The method according to claim1, wherein the agglomeration aid comprises polyaluminum chloride; ferricchloride; cationic polymers selected from the group consisting ofpolyamines, polyacrylamides, polydiallyldimethylammonium chloride;aluminum sulfate and mixtures thereof.
 5. The method according to claim2, wherein the filtration enhancement aid comprises diatomaceous earth,cellulose, chitin, aluminum sulfate, perlite and mixtures thereof. 6.The method according to claim 1, wherein the halogenating agent isselected from the group consisting of sodium hypochlorite, lithiumhypochlorite, calcium hypochlorite, chlorine, hypochlorous acid,bromine, hypobromous acid, N-chlorosuccinimide, sodium hypobromite,pyridinium bromide perbromide, N-bromosuccinimide,dichlorodimethylhydantoin, bromochlorodimethylhydantoindibromodimethylhydantoin, dichloroisocyanurate, andtrichloroisocyanurate.
 7. The method according to claim 1, wherein step(i) comprises adding the halogenating agent in an amount to raise theconcentration of the initial active free halogen to a level betweenabout 20 ppm and about 40 ppm.
 8. The method according to claim 2,wherein the filtering system comprises a sand filter, diatomaceous earthor a cartridge filter.
 9. The method according to claim 1 wherein theconcentration of active free halogen is reduced by adding a halogenneutralizer to the recreational body of water.